period after BC?

had my period the 8th-11th of this month, was supposed to start a new pack of BC the 11th, but the pharmacy couldn't get the pills and my gyno never called me anything else in. so i've been off birth control since last month(may) basically. today i had slight cramping which i thought i just had to poop and i woke up and there's brown blood(which i know is old blood) i know not being on BC will mess my cycle up a little so is this my period again???